Ink jet printers generally dispense ink onto a substrate through a nozzle plate that has an array of holes. Ink is loaded behind the plate and an actuator causes the ink to be pushed through the hole onto the print substrate. Generally, the number of holes corresponds to a particular number of dots per inch (dpi) for a printing system.
In many current ink jet printers, the actuators are an array of piezoelectric actuators. When the image data representing an image dictates that a drop should be printed onto the print substrate at a particular place, the piezoelectric actuator is activated. The actuator's motion or vibration causes the ink to be pressed through the hole in the nozzle plate onto the substrate.
It is possible to replace the piezoelectric actuators with an electrostatically actuated system using a flexible membrane. The flexible membrane may reside behind the nozzle plate where the ink fills between the flexible membrane and the nozzle plate. An electrode plate to actuate regions of the membrane may reside behind the flexible membrane and across a small air gap from it.